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 Post subject: Re: My Mexican Amber article
PostPosted: Tue Nov 05, 2013 11:31 am 
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Hi Yeti,haven't try either,that sounds to formulaic,but the general characteristic to me it seems is more like copal than amber,like many others wrote including yourself,so for me the crucial aspect is the stickiness and the melting point, no amber that I know behaves that way except copals,in 30 years I have carved several hundreds of kilos of ambers of many places and copals from Colombia, Dominican republic,new Zealand ,Africa,Kalimantan, and now Sumatra,but again my perspective is from the carving and how materials behave when exposed to the carving process, only a point of view and not a definitive answer.


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 Post subject: Re: My Mexican Amber article
PostPosted: Wed Nov 06, 2013 7:34 am 
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Still I thought the most conclusive criteria to determine amber from copal chemically was the sensitiveness/unsensitiveness to organic solvents.
Ok maybe the indonesian material is just an in-between, and gemologists will have to refine their definition from now on.

Isi speaking (not Yeti !)


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 Post subject: Re: My Mexican Amber article
PostPosted: Sat Nov 16, 2013 11:57 am 
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Welcome to the chit chat, gemart.
While i agree with you on melting points vs. Powdering when using the tools, Isis has a valid point. The malay "amber" samples i have are unaffected by acetone other than giving a good cleaning to the surface. To me, that means they have fossilized into amber, a chemical analysis would help with this. BTW, I used the word sticky to describe the surface a few days later but perhaps a better word is tactile, as compared to baltic or mexican. I dont understand why, unless perhaps its the red flow inclusion contaminating the amber. The malay is nothing like the columbian copal i have when acetone is used on it, the copal just turns to sap while the malay is basically unaffected. Both do gum up under a scroll saw or dremel though. It's interesting.


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 Post subject: Re: My Mexican Amber article
PostPosted: Sat Nov 16, 2013 7:18 pm 
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Thank you Yeti,
I would think that the Sumatran(haven't seen the Malay material yet) "amber" did not completely went to the full process to acquire the characteristics that other ambers have.
Maybe it was not exposed to enough pressure to complete the natural polymerization that other ambers have,therefore becoming susceptible to oxidation 10 times faster than other ambers,making it necessary to be repolished every few months,I would include the word sticky,some friends where selling it at the Tucson show and after several hours under the sun the Sumatran ambers were in fact quite sticky,another issue I have with the material is its waxy look, it never reaches the clarity and brilliance that makes amber a gem,although a friend that has a lapidary workshop in Indonesia told me that some pieces had some nice clarity, in the several hundreds of cabochons that I saw at his workshop there was none,the only thing I like about the Sumatran amber are some of its blue colors,honestly,I could care less if it's labeled amber or not,but due to its general characteristics I would prefer not to use it given the wide availability of ambers of good and great quality,like its neighbor Burmite or the Mexican ,Dominican and Baltic Ambers among others.


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 Post subject: Re: My Mexican Amber article
PostPosted: Mon Nov 18, 2013 9:47 am 
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Malay...hmmmm, meant indonesian, my bad.
Anyway, for what its worth i agree with your comments.
I particularly like the Mexican amber for the flourescence and workability but nothing smells like the baltic powder when cutting .

Hey, after 30 years you must have some nice samples can you put any pics up?


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 Post subject: Re: My Mexican Amber article
PostPosted: Fri Feb 27, 2015 12:48 pm 
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Image

The detail and preservation of this insect is amazing. I got it in Simojovel, Chiapas.

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http://www.mexicanamber.org.uk


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 Post subject: Re: My Mexican Amber article
PostPosted: Mon May 02, 2016 1:38 am 
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Very informative article.


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